Moisture-Stable FAPbI₃ Perovskite Achieved by Atomic Structure Negotiation

Broad impact in the research community may be anticipated when a material's properties are capable of being manipulated artificially. Such a possibility has been explored here in the FAPbI₃ perovskite structure of perovskite solar cells, which involves undesirable phase transition at working temperature, despite many attempts to resolve the issue. Essential steps have been taken here toward solving this problem by adopting an opposite strategy to incorporate the water molecules into the perovskite structure under the current materials framework by new structural physics maneuvering. The secondary bonding of the perovskite structure has been relocated, which altered the microstructure to remove the internal strain that caused the phase transition, resulting in not only a 10-fold enhancement in the moisture/structure stability but also a bandgap comparable to that of the favored α-FAPbI₃. All this opens an unprecedented avenue in perovskite research, which will hopefully be of intrinsic interest to the broad materials research community as well.